Method for deblurring an image

• US 8,654,201 B2
• Filed: 02/23/2005
• Issued: 02/18/2014
• Est. Priority Date: 02/23/2005
• Status: Expired due to Fees

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Lim, Suk Hwan, Silverstein, D. Amnon
• Primary Examiner(s): Tran, Sinh
• Assistant Examiner(s): LE, TUAN H
• Application Number:
  US11/064,128
• Publication Number:
  US 20060187308A1
• Time in Patent Office: 3,282 Days
• Field of Search: 348/208.4, 348/208.99, 348/221.1, 348/362
• US Class Current: 348/208.4
• CPC Class Codes: G06T 2207/20056 Discrete and fast Fourier transform, [DFT, FFT]
• CPC Class Codes: G06T 5/50 using two or more images, e.g. averaging or subtraction
• CPC Class Codes: G06T 5/73 Deblurring; Sharpening
• CPC Class Codes: H04N 23/68 for stable pick-up of the scene, e.g. compensating for camera body vibrations
• CPC Class Codes: H04N 23/6845 by combination of a plurality of images sequentially taken

Abstract

A method for deblurring an image. A first image is captured. A second image is captured, wherein the second image is more blurred and more exposed than the first image. The second image is deblurred based on the first image.

Claims

1. A method, comprising:

capturing a first image;

capturing a second image, wherein said second image is more blurred and more exposed than said first image;

generating a blur kernel based on said first image and said second image, wherein the blur kernel models blur in said second image, and said generating of said blur kernel comprises calculating a Fourier transform of said first image, calculating a Fourier transform of said second image, calculating of a ratio from said Fourier transform of said second image and said Fourier transform of said first image, and deriving the blur kernel based on an inverse Fourier transform of said ratio; and

producing a deblurred image based on a deblurring of said second image with said blur kernel, wherein the deblurring is regularized based on said first image and a regularization parameter that constrains deviation of the deblurred image from said first image.

2. The method as recited in claim 1, wherein said capturing of said first image comprises capturing said first image using a shorter exposure time than said second image.

3. The method as recited in claim 1, wherein said capturing of first image comprises capturing said first image using a smaller aperture size than said second image.

4. The method as recited in claim 1, wherein said deblurring comprises deblurring said second image according to a regularized second order minimization by calculating a deblurred image that does not substantially deviate from said first image.

5. The method of claim 1, wherein said deblurring comprises determining an image j that minimizes:

∥

iL−

h*j∥

²+λ

∥

iS−

j∥

²

where iS is an image derived from the first image, iL is an image derived from the second image, h is the blur kernel, * represents a convolution process, and λ

is a regularization parameter.

6. A method, comprising:

capturing a first image;

capturing a second image, wherein said second image is more blurred and more exposed than said first image;

generating a blur kernel based on said first image and said second image, wherein the blur kernel models blur in said second image, wherein said generating said blur kernel comprises calculating an auto-correlation of said second image, calculating a cross-correlation between said first image and said second image, and deriving said blur kernel based on said auto-correlation and said cross-correlation; and

producing a deblurred image based on a deblurring of said second image with said blur kernel, wherein the deblurring is regularized based on said first image and a regularization parameter that constrains deviation of the deblurred image from said first image.

7. A non-transitory computer-usable medium having computer-readable program code embodied therein for causing a computer system to perform a method, said method comprising:

capturing a first image;

capturing a second image, wherein said second image is more blurred and more exposed than said first image;

generating a blur kernel based on said first image and said second image, wherein the blur kernel models blur in said second image, and said generating comprises calculating a Fourier transform of said first image, calculating a Fourier transform of said second image, calculating of a ratio from said Fourier transform of said second image and said Fourier transform of said first image, and deriving the blur kernel based on an inverse Fourier transform of said ratio; and

producing a deblurred image based on a deblurring of said second image with said blur kernel, wherein the deblurring is regularized based on said first image and a regularization parameter that constrains deviation of the deblurred image from said first image.

8. The computer-usable medium as recited in claim 7, wherein said capturing comprises capturing said first image using a shorter exposure time than said second image.

9. The computer-usable medium as recited in claim 7, wherein said capturing comprises capturing said first image using a smaller aperture size than said second image.

10. The computer-usable medium as recited in claim 7, wherein said deblurring comprises deblurring said second image according to a regularized second order minimization by calculating a deblurred image that does not substantially deviate from said first image.

11. The computer-usable medium of claim 7, wherein said deblurring comprises determining an image j that minimizes:

∥

iL−

h*j∥

²+λ

∥

iS−

j∥

²

where iS is an image derived from the first image, iL is an image derived from the second image, h is the blur kernel, * represents a convolution process, and λ

is a regularization parameter.

12. A non-transitory computer-usable medium having computer-readable program code embodied therein for causing a computer system to perform a method, said method comprising:

capturing a first image;

capturing a second image, wherein said second image is more blurred and more exposed than said first image;

generating a blur kernel based on said first image and said second image, wherein the blur kernel models blur in said second image wherein said generating comprises calculating an auto-correlation of said second image, calculating a cross-correlation between said first image and said second image, and deriving said blur kernel based on said auto-correlation and said cross-correlation; and

producing a deblurred image based on a deblurring of said second image with said blur kernel, wherein the deblurring is regularized based on said first image and a regularization parameter that constrains deviation of the deblurred image from said first image.

13. A system, comprising:

a computer-readable medium storing computer-readable instructions; and

a data processing unit coupled to the computer-readable medium, operable to execute the instructions, and based at least in part on the execution of the instructions operable to perform operations comprising

capturing a first image and a second image, wherein said second image is more blurred and more exposed than said first image;

generating a blur kernel based on said first image and said second image, wherein the blur kernel models blur in said second image; and

deblurring said second image with said blur kernel based on said first image, wherein in said deblurring the data processing unit is operable to perform operations comprising determining an image j that minimizes;

∥

iL−

h*j∥

²+λ

∥

iS−

j∥

²

where iS an image derived from the first image, iL is an image derived from the second image, h is the blur kernel, * represents a convolution process, and λ

is a regularization parameter.

14. The system as recited in claim 13, wherein in said capturing the data processing unit is operable to perform operations comprising capturing said first image using a shorter exposure time than said second image.

15. The system as recited in claim 14, wherein in said capturing the data processing unit is operable to perform operations comprising capturing said first image is captured using a smaller aperture size than said second image.

16. The system as recited in claim 13, wherein in said generating said data processing unit is operable to perform operations comprising:

calculating an auto-correlation of second image;

calculating a cross-correlation between said first image and said second image; and

deriving said blur kernel based on said auto-correlation and said cross-correlation.

17. The system as recited in claim 13, wherein in said generating said data processing unit is operable to perform operations comprising:

calculating a Fourier transform of said first image;

calculating a Fourier transform of said second image;

calculating a ratio from said Fourier transform of said second image and said Fourier transform of said first image; and

deriving the blur kernel based on an inverse Fourier transform of the ratio.